aa cup 

The smallest possible breast size.

Measuring less than 1 inch difference between the bust and the below bust (band) measurments.

aa cup is basically a training bra.

aa cup by asd324 May 6, 2009

aa cup 

Part of the Itty Bitty Tittie Committee

Did you hear about Steph, Cam and Nash? We thought they were guys with there AA Cups

aa cup by mattyraw October 1, 2016

AA Cup 

The smallest bra cup size, mostly training bras but some AA cup bras and pushup bras are made for unfortunate adult women with AA cups

"Your AA cup bra is so small!"

"I still wear a AA cup, I can fit into all my training bras"

"Sorry, we don't sell AA cups here, have you tried gap kids? I heard they have a good training bra selection"

AA Cup by Embarrassedonlive March 19, 2025

AA Cup 

Typically pronounced as "double A Cup".

Brassiere cup size intended for overbust from nothing up to 1 inch larger than the underbust, especially the larger range in the rare case of AAA also being used, making it not strictly the smallest size though it often is.

Otherwise included in the A range.

Young girls will often get training bras measuring a AA cup.

AA Cup by ApricotFields May 19, 2025

AA-cup 

A bra size so small that many scientists are baffled how some girls have breasts that small and why it even exists

Guy: What bra size do you wear?

Girl: I'm AA-cup.

Guy: THAT SMALL!? I don't think you need a bra at all if its that small

AA-cup by Expertinculturedthings May 4, 2022